Casein is the principal protein of milk, with the casein being present as micelles, that is, naturally occurring proteinaceous microparticles comprising a calcium caseinate-phosphate complex having a diameter of from about 0.1 to 0.4 microns. It has been suggested heretofore that concentrated, substantially non-aggregated casein micelles obtained by the ultrafiltration of skim milk may be used as a fat substitute in certain food products such as whipped or quiescently frozen or refrigerated desserts, puddings, whipped toppings, sauces, dips, and the like.
However, when casein is isolated for commercial utilization, such as in the production of acid casein or alkali metal caseinates, the micelles are destroyed. Consequently, since such commercially available casein products no longer contain casein in micelle form, they are not suitable for use as a fat replacer.